PROJECT SUMMARY This application is for a K08 award for Rebecca Berhanu MD, an Instructor at Boston University?s Department of Global Health in the School of Public Health, who is training to become an independent investigator in the field of molecular epidemiology and tuberculosis (TB) transmission research. TB is the leading infectious cause of death globally and the number one cause of death amongst people with HIV. The identification of recent TB transmission clusters by whole genome sequencing (WGS) methods offers unique insight into transmission patterns which cannot be obtained through traditional contact tracing. The overall research objective is to use WGS coupled with molecular clock, phylogenic and transmission cluster analysis to characterize transmission of rifampin and multi-drug resistant (RR/MDR) TB in Johannesburg, South Africa. The aims of the study are to: 1) Use WGS data to calculate the molecular clock of RR/MDR-TB, 2) Use single-nucleotide polymorphism (SNP)-based cluster analysis and Bayesian transmission analysis to identify recent TB transmission clusters or RR/MDR-TB, and evaluate the impact of HIV status, CD4 count and antiretroviral therapy (ART) on the likelihood of transmitting TB and 3) Determine if WGS transmission cluster identification augmented with demographic and social-network data can identify non-household locations of recent RR/MDR-TB transmission. Dr. Berhanu will receive mentorship from a team of inter-disciplinary experts in TB epidemiology, bioinformatics and TB genomics. Her primary mentor, Dr Horsburgh, is a Professor of Medicine and Epidemiology at Boston University and has over 30 years? experience in TB clinical and translational research. Her co-primary mentor, Dr. Karen Jacobson, an Assistant Professor of Medicine at Boston University, is an expert in TB epidemiology in high-burden settings and has worked extensively in South Africa using TB molecular data. Dr. Berhanu?s Advisory Board includes Dr. Maha Farhat, Assistant Professor of Biomedical Information at Harvard University, who has published extensively on resistance mutation characterization and markers of recent transmission using TB genomic data; Dr. Nazir Ismail, head of the Centre for Tuberculosis of the NICD in Johannesburg, is an expert in TB molecular epidemiology, and Dr. Evan Johnson, Associate Professor of Medicine and Biostatistics at Boston University, with expertise in bioinformatics methodology. Dr. Berhanu?s training plan links to the proposed research aims: establish a solid foundation in epidemiology; and develop new skills in bioinformatics, phylogenetics and transmission analysis using WGS data. Training will be accomplished through a combination of didactic courses, workshops, and practicums in South Africa and Boston. These training and research activities will allow Dr. Berhanu to mature into an independent investigator and provide a basis for an R01 using molecular and social network data to identify transmission hotspots and areas for targeted case-finding.